It is common practice to mount large dynamoelectric machines on concrete foundations that are covered with a flat metal soleplate that affords a smooth mounting surface for the machine. To prevent the machine from moving axially on such a smooth soleplate, in response to axial drive or mounting thrusts being applied to the machine, it is conventional practice to secure holding blocks to the soleplate in abutting relationship with opposite ends of the machine pedestals. The holding blocks are ordinarily fixed in position by inserting a number of metal dowels through them and the soleplate. The thrust loading anticipated on the motor pedestal will determine the number of dowels needed in a given application to prevent the dowels from being sheared off. Finally, in order to have as little play as possible between the holding blocks and the machine pedestals, a plurality of shims are typically mounted between these component parts in an attempt to substantially eliminate all slack in the mounting assembly.
These conventional prior art mounting assemblies have several shortcomings. One of these shortcomings is that a relatively large amount of space is frequently needed to accommodate sufficiently large holding plates to receive all of the dowels necessary to accommodate the shear forces encountered with dynamoelectric machines that are subject to large axial thrusts. For example, holding plates of a foot or more in width would be necessary to receive the large number of dowels necessary to resist the axial thrusts of several hundred thousand pounds that are often encountered on modern day large dynamoelectric machines. The provision of such additional space frequently is not a desirable design requirement in powerhouse and industrial applications where space is at a premium.
Another shortcoming of such prior art mounting assemblies is that it is not possible with the shim arrangements utilized therein to completely eliminate slack in the mounting assemblies. Accordingly, when axial thrust loads are alternately applied to a machine pedestal secured by such an assembly this slack allows the machine to shift on the foundation soleplate thus causing a hammering effect that tends to render the mounting assembly ineffective over a period of time.